Lid for a drinking container and the drinking container

ABSTRACT

A lid for a drinking container includes a circular upper portion including a bayonet fastening device, and a circular lower portion including a counterpart bayonet fastening device. The circular upper portion includes a first and second openings and the circular lower portion includes corresponding first and second openings. The bayonet fastening device of the circular upper portion and the counterpart bayonet fastening device of the circular lower portion are configured to be coupled with each other so to guide the circular upper portion and the circular lower portion to be turned in relation to each other around a common axis in a manner enabling the first openings being aligned and the second openings being aligned in an opening position, and enabling the first openings being un-aligned and the second openings being un-aligned in a closing position.

TECHNICAL FIELD OF THE INVENTION

The invention relates to a lid for a drinking container, such as especially a lid for a coffee or tea mug for preventing any leaking or spilling of liquid contained the mug in use. In addition the invention relates to a method for manufacturing the lid for the drinking container as well as to a drinking container comprising or using the lid.

BACKGROUND OF THE INVENTION

Numbers of different lid for drinking containers are known, where one of the simplest one is a plastic flat lid having a small drinking hole on the top cover area and a bent rim portion, which is to be settled around the rim portion of a cardboard coffee mug. Also rubber lids are known, where the drinking hole is sealed with a sealing member. The sealing member has typically a small arm and is hinged so that it can be turned away from the drinking hole for drinking the liquid inside the mug, and again it can be turned over the drinking hole for a sealing purpose. The sealing member is pressed against the drinking hole in sealing position by spring force of the arm. Furthermore more complex structures are also known, such as lids with inner sealing members having e.g. springs and sealing balls, where the balls are pushed by the springs into and away from the drinking hole for example when the lid is turned around.

There are however some disadvantages relating to the known prior art, such as the plastic flat lid having a small drinking hole does not have any sealing function for the drinking hole. In addition the rubber lid with the sealing member is not tight enough because the spring force of the arm is often loosen and especially because the small arm is easily bent or even swing away from the hole area, for example when the mug is put into a bag. Furthermore lids with inner sealing members having e.g. springs and sealing balls are very complex to manufacture and additionally extremely difficult to keep clean, and often there is also no clear feedback or indication to the user when the lid is in an open or closed position.

SUMMARY OF THE INVENTION

An object of the invention is to alleviate and eliminate the problems relating to the known prior art. Especially the object of the invention is to provide a lid for a drinking container, which is easy to use and keep clear and additionally seals the drinking hole in liquid tightly and reliable way so that any unwanted opening of the drinking hole is prevented. In addition an object is to provide a lid, which provides a clear indication to the user whether the lid is in an open or closed position.

The object of the invention can be achieved by the features of independent claims.

The invention relates to a lid according to claim 1. In addition the invention relates to a drinking container according to claim 19, and to a manufacturing method of the lid according to claim 20.

According to an embodiment of the invention a lid for a drinking container comprises upper and lower portions. The upper portion is a circular upper portion, and it comprises a bayonet fastening device. The lower portion is a circular lower portion and it comprises a counterpart bayonet fastening device, which is suitable for receiving the bayonet fastening device of the upper portion and thereby enabling easy attaching/detaching between said two portions. As an example the bayonet fastening device of the upper portion is male bayonet fastening device, and the counterpart bayonet fastening device of the lower portion is female bayonet fastening device, or vice versa. The circular upper portion comprises additionally first and second openings, namely one for drink outlet and one for compensation air inlet. In addition the circular lower portion comprises corresponding first and second openings, one for drink outlet and one for compensation air inlet.

The bayonet fastening device of the circular upper portion and the counterpart bayonet fastening device of the circular lower portion are advantageously configured so that they can be coupled with each other in use, and in more particularly so that said circular upper and lower portions are coupled with each other in a releasable manner via said bayonet fastening devices.

The coupling is advantageously implemented so to guide the circular upper portion and the circular lower portion in the manner where they can be turned in relation to each other around a common axis. When turning the portions, they enable the first openings being aligned and the second openings being aligned in an opening position and thereby allowing liquid flow through via the first openings and compensation air inlet via the second openings. In addition the portions enable the first openings being un-aligned and said second openings being un-aligned in a sealing manner in a closing position, so when the portions are turned in the manner where the openings are not aligned. In the closing position the openings of the drinking container are sealed in a liquid tightly manner and thereby any leaking or spilling of liquid contained the mug or the drinking container coupled to the lid can be prevented.

According to an embodiment the lid, advantageously the circular lower portion, comprises a fastening thread, which is arranged to fasten and unfasten the lid to and from the drinking container when the lid (circular lower portion) is turned in relation to said drinking container. This confirms safe and reliable fastening so that the lid construction remain closed to the drinking container.

According to an embodiment the circular upper portion comprises a first guiding member, such as a lip or tongue and the circular lower portion comprises a counterpart first guiding member, such as a slot. When the lip of the upper portion is aligned with the slot of the lower portion, the circular upper and lower portions can be attached to and detach from each other. When the circular upper portion is then turned (after attaching) an opening and closing positions can be achieved. In addition, when said first and second guiding members are un-aligned with each other, the guiding members (such as groove and counterpart groove) of the bayonet fastening devices of the upper and lower portions guide the turning of the upper and lower portions in relation to each other around the common axis so that the upper and lower portions are kept tightly together.

The circular upper and/or lower portions may also comprise feedback providing mechanics for providing haptic, tactile and/or audible feedback, when said circular upper portion is turned in relation to said circular lower portion to the opening (drinking) and/or closing positions. The feedback may also be generated when the upper portion is turned in relation to said circular lower portion to the detaching position. The tactile providing mechanics is advantageously implemented by snaps or half-cuts. In addition the lid comprises advantageously markings in the rim area of the circular upper and lower portions denoting “open”, “close” and “detach” positions. The markings may be implemented by color dots or notch or engravings in the structure of upper and lower portions to be turned in relation to each other.

According to an embodiment the lid comprises a stop member for guiding the first and second openings of the upper and lower portions to stop in the un-aligned, so the closing (un-leaking) position, when said circular upper portion is turned in relation to the circular lower portion. The stop member is also configured to prevent any additional mutual turning of said circular upper and lower portions. If the upper portion is still tried to turned in relation to the lower portion (e.g. in clock-wise), the stop member forces also lower portion to be turned thereby just tightening the possible thread connection between the lid (lower portion) and the drinking container. In addition said stop member is advantageously configured to guide the circular upper and lower portions to stop in the detaching position, when said circular upper portion is turned in relation to the circular lower portion advantageously in another direction. If the upper portion is still tried to turned in relation to the lower portion (e.g. in counter clock-wise), the stop member forces also lower portion to be turned thereby just loosening the possible thread connection between the lid (lower portion) and the drinking container.

The stop member is advantageously implemented by mechanical structures in the circular upper and lower portions, such as a protruding lip member in the upper portion and a counterpart protruding lip member in the circular lower portion.

According to an embodiment said guiding members, said tactile providing mechanics and/or said stop members are arranged in at least one of said bayonet fastening device. It is to be noted that said guiding members, said tactile providing mechanics and/or said stop members can be positioned freely into the circular upper and lower portions or bayonet devices thereby enabling number or different positions to be locked, attach, guide the circular upper and lower portions and/or provide feedbacks. In addition they may be implemented so that they provide haptic, tactile and/or audible feedback for the user when closing or opening the lid or turned into the detaching position, such as snap sound and clear mechanical resistance change felt before snapping into closed or opened position, for example. Additionally or alternatively the lid (upper and lower portions) may comprise also visual alignment or indication for the closed or opened positions, as well as also for the attaching/detaching position.

In addition according to an embodiment the first and second openings of the circular lower portion are provided with sealing members, which are arranged to be pressed against the circular upper portion in a non-opening position in a liquid-tightly sealing manner. The sealing members are advantageously arranged around the opening areas so to prevent any leakage into the space between circular upper and lower portions.

According to an embodiment the lid or circular upper portion comprises a sealing member, which is configured to locate between said circular upper and lower portions, when said circular upper and lower portions are coupled to each other. In addition the circular lower portion is provided with a sealing member, said sealing member being arranged to be positioned between said circular lower portion and the drinking container, when said circular lower portion and the drinking container are coupled to each other and sealed.

The sealing members are advantageously soft rubber or silicone members or any other elastomer (e.g. TPE—thermoplastic elastomers, TPV—thermoplastic vulcanizate, TPU—thermoplastic polyurethane), which are suitable for providing effective liquid sealing. In addition the sealing members are advantageously configured to be manually detachable e.g. for cleaning purposes.

Furthermore, according to an advantageous embodiment the circular lower portion comprises two structural portions, one of which comprises hard material, like plastic, and one of which comprises softer portion, which can functioning as said sealing member. Also the circular upper portion may plastic, and another portion of which comprises softer portion, which can functioning as said sealing member. In addition the top surface of the circular upper portion comprises advantageously an asymmetrically shaped portion or is asymmetrically shaped for better user drinking experience. Further the top surface of the circular upper portion may comprise a matte or rough outer surface for increasing turning grip.

The present invention offers advantages over the known prior art, such as an easy and liquid-tight manner to close the drinking hole of the lid and an easy and hygienic way to open it for drinking. The drinking hole can be closed in a reliable way so that any unwanted opening of the drinking hole is effectively prevented. In addition the invention provides the lid, which is easy to couple with the drinking container in a liquid-tight manner. The lid according to the invention can be implemented without any springs or sealing balls, which makes the structure and manufacturing process quite simple. In addition the lid of the invention is easy to use and keep clear. Moreover the lid provides a clear indication to the user whether the lid is in an open or closed position or position enabling attaching/detaching the circular upper and lower portions.

BRIEF DESCRIPTION OF THE DRAWINGS

Next the invention will be described in greater detail with reference to exemplary embodiments in accordance with the accompanying drawings, in which:

FIG. 1 illustrates a principle of an exemplary drinking container with a lid according to an advantageous embodiment of the invention,

FIG. 2 illustrates an exemplary lid according to an advantageous embodiment of the invention,

FIG. 3 illustrates exemplary circular upper and lower portions of the lid according to an advantageous embodiment of the invention,

FIG. 4 illustrates exemplary structural parts of the circular upper and lower portions of the lid according to an advantageous embodiment of the invention,

FIG. 5 illustrates an example of a cross section of an exemplary lid structure according to an advantageous embodiment of the invention,

FIG. 6 illustrates exemplary operation of the lid according to an advantageous embodiment of the invention,

FIGS. 7A-7C illustrate another exemplary operation of the lid according to an advantageous embodiment of the invention

FIGS. 8A-8B illustrate exemplary circular upper and lower portions with bayonet devices according to an advantageous embodiment of the invention, and

FIGS. 9A-9B illustrate exemplary drinking container with an example lid according to an advantageous embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a principle of an exemplary drinking container 100 with a lid 200 according to an advantageous embodiment of the invention. The typical drinking container 100 is e.g. a coffee or tea mug, but can of course be any drinking container capable of carrying liquid inside and with which the lid 200 can be used for preventing any leakage or spilling of the liquid.

FIGS. 2-8B illustrate different views of an exemplary lid 200 according to an advantageous embodiment of the invention, where in FIGS. 2 and 6 the lid is assembled for use mode, and where in FIG. 3 the lid is divided into the circular upper portion 201 and circular lower portion 202 from which the lid is formed. In addition FIG. 4 illustrates an exemplary lid structure, where the circular upper portion comprises two parts 201 a, 202 b and the circular lower portion 202 comprises two parts 202 a, 202 b. FIG. 5 illustrates a cross section figure of the circular upper portion 201 of an exemplary lid structure 200.

As can be seen e.g. in FIGS. 3, 4, 5 and especially 8A and 8B the circular upper portion 201 comprises a male bayonet fastening device 203, and the circular lower portion 202 comprises a counterpart female bayonet fastening device 204. The circular upper portion 201 comprises additionally first opening 205 a and second opening 206 a, namely one for a drink outlet 205 a and one 206 a for a compensation air inlet. In addition the circular lower portion 202 comprises corresponding first opening 205 b and second opening 206 b, one 205 b for the drink outlet and one 206 b for the compensation air inlet. When the lid is assembled, as is the case in FIGS. 2 and 6, the lid comprises in the drinking mode the first opening as said drink outlet 205 and the second opening 206 as for a compensation air inlet.

The bayonet device 203 of the circular upper portion 201 and the counterpart bayonet device 204 of the circular lower portion 202 are configured so that they can be coupled with each other in a releasable manner. The bayonet devices enable easy attaching/detaching between the circular upper and lower portions. In addition the bayonet devices guide the circular upper portion 201 and the circular lower portion 202 so that they can be turned in relation to each other around a common axis 207 between the opening, closing and detaching positions, as can be seen especially in FIGS. 6 and 7A-7C.

As can be seen in FIG. 4 the circular lower portion 202 comprises two structural portions, one 202 a of which comprises hard material, like plastic and one 202 b of which comprises softer portion functioning e.g. as a sealing member. The circular upper portion 201 comprises also two structural portions, one 201 a of which comprises hard material, like plastic, and another portion 201 b, which comprises softer portion functioning e.g. as a sealing member. The sealing member 201 b is advantageously arranged to be pressed against the circular upper and/or lower portion 202 in a non-opening position in a liquid-tightly sealing manner. In addition the sealing member 202 b is arranged to be positioned between the circular lower portion 202 and the drinking container 100, when said circular lower portion and the drinking container are coupled to each other and sealed.

The sealing member is advantageously configured to seal any conduits between first openings 205 a, 205 b as well as between said second openings 206 a, 206 b, when said openings are un-aligned in said closing position. According to an embodiment the sealing member 239, 240 may be inserted into the circular upper portion from the bottom also to ensure sealing between upper portion and lower portion while in the drinking and locking position (pressure seal). The sealing member area is advantageously kept to a minimum to reduce turning friction. There might also be a recess(es) in the sealing member in order to enable user removal for cleaning and re-attaching (pulling out with finger). In addition the sealing members 239, 240 may comprise also small protruded area 239 a, 240 a, which are configured to further press the sealing member against the drinking and air holes 206 a, 205 b, when the circular upper portion is turned into the closed position. The sealing member comprises or is for example soft rubber, silicon or any other elastomer (e.g. TPE—thermoplastic elastomers, TPV—thermoplastic vulcanizate, TPU—thermoplastic polyurethane).

As can be seen e.g. in FIGS. 8A and 8B the circular upper portion 201 comprises a guiding member 231 and the circular lower portion 202 comprises a counterpart guiding member 232. The guiding members are configured to guide the circular upper and lower portions 201, 202 to be attached to and detach from each other in predefined position. The guiding members 231, 232 are advantageously arranged into the bayonet devices 203, 204. In addition the guiding members are advantageously implemented by a lip or tongue 232 and the corresponding groove 231.

In addition the lid 200 comprises a stop members 236, 237 a, 237 b for guiding the first and second openings 205, 206 of the upper and lower portions 201, 202 to stop in the un-aligned, so the closing (un-leaking) position (237 a), when said circular upper portion 201 is turned 207 in relation to the circular lower portion 202. In addition said stop members 236, 237 a, 237 b are advantageously configured to guide the circular upper and lower portions 201, 202 to stop in the detaching position (237 b), when said circular upper portion is turned 207 in relation to the circular lower portion 202 advantageously in another direction than previously. The stop members are advantageously implemented by mechanical structures in the circular upper and lower portions, such as a protruding lip member 236 in the upper portion and a counterpart protruding lip members 237 a, 237 b in the circular lower portion.

The lid is additionally configured, in the lock position (237A), to further tighten the fastening of the thread 238 between the drinking container 100 and the lid 200, if an additional turning force is applied so the stop members 236, 237A are forced against each other (e.g. in clock-wise). Additionally the lid may also be configured, in the detach position (237B), to loosen the fastening of the thread 238 between the drinking container 100 and the lid 200, when applied an additional turning force so the stop members 236, 237B are forced against each other (e.g. in counter clock-wise). The further tighten or loosening is achieved by the stop members 236, 237 a, 237 b so that the stop member 236 of the circular upper portion forces also the lower portion to be turned via said stop member 237A, 237B thereby just further tightening or loosening (depending on the rotation direction) the possible thread connection between the lid (lower portion) and the drinking container.

In addition, according to an example there are arranged stopper ribs between stop members 237A and 237B, which is configured to prevent accidental detachment of the circular upper portion 201 from the lower portion, so that user has to apply force to move from “open” to “detach” position. The stopper ribs are not shown in the Figures.

FIGS. 6 and 7A-7C illustrate the operation of the lid 200 according to an advantageous embodiment of the invention, where the lid 200 has three different positions, namely open, closed and attaching/detaching positions.

The circular upper portion is advantageously provided with a marking member 233, and the circular lower portion is also provided with marking members 233A, 233B, and 233C denoting different positions (open, closed, attach/detach) of the lid. According to an embodiment, when turning the portions 201, 202 so that the marking members 233, 233A are aligned, then also said guiding members 231, 232 are aligned in same line thereby allowing attaching/detaching of the circular upper and lower portions (as is the case in FIG. 7A).

When turning the portions 201, 202 so that the marking members 233, 233B are aligned, then also the first openings 205 a, 205 b are aligned and the second openings 206 a, 206 b are aligned in an opening position (FIG. 7B) thereby allowing liquid flow through via the first openings 205 and compensation air inlet via the second openings 206.

In addition, when turning the portions 201, 202 so that the marking members 233, 233C are aligned, then the portions 201, 202 arrange the first openings 205 a, 206 b being un-aligned and said second openings 205 b, 206 b being un-aligned in a sealing manner in a closing position (FIG. 7C), so when the portions are turned in the manner where the openings are not aligned. In the closing position the openings of the drinking container are sealed in a liquid tightly manner and thereby any leaking or spilling of liquid contained the mug can be prevented.

According to an example, once the circular upper portion is attached to the lower portion, the central bayonet mechanics 203, 204 enable the upper portion to be turned (e.g. 60° in clock-wise) into a drinking position. An additional turning (e.g. 45° turning in clock-wise) locks the upper and lower portions to prevent leakage. Once the locking position is reached a stop feature prevents additional turning. Additional turning force (clock wise) applied in the lock position will lead to further fastening of the thread fastening between cup and lid, as is discussed elsewhere in this document.

The circular upper and/or lower portions 201, 202 may also comprise feedback providing mechanics 234, 235A, 235B, 235C for providing haptic, tactile and/or audible feedback, when said circular upper portion 201 is turned in relation to said circular lower portion 202 to said opening or closing (drinking and locking) positions or to the attaching/detaching position. The feedback members are implemented for example by snaps or half-cuts 234, 235A, 235B, 235C so that they are configured to provide haptic, tactile and/or audible feedback and to further help and guide said first openings 205 a, 205 b being aligned to stop and said second openings 206 a, 206 b being aligned to stop in an opening (drinking) position, closed position, and/or attaching/detaching position, when said circular upper portion 201 is turned in relation to said circular lower portion 202.

FIGS. 9A-9B illustrate exemplary drinking container 100 with an example lid 100 according to an advantageous embodiment of the invention, where the circular lower portion 202 of the lid comprises fastening thread 238 arranged to fasten and unfasten said lid to and from said drinking container 100, when said circular lower portion 202 (or the lid) is turned in relation to said drinking container.

The invention has been explained above with reference to the aforementioned embodiments, and several advantages of the invention to these embodiments, but comprises all possible embodiments within the spirit and scope of the inventive thought and the following patent claims. In addition it is to be noted that the features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. 

1. A lid for a drinking container, wherein the lid comprises: a circular upper portion comprising a bayonet fastening device, and a circular lower portion comprising a counterpart bayonet fastening device, wherein: said circular upper portion comprises a first and second openings and said circular lower portion comprises corresponding first and second openings, wherein: said bayonet fastening device of the circular upper portion and said counterpart bayonet fastening device of the circular lower portion are configured to be coupled with each other so to guide the circular upper portion and the circular lower portion to be turned in relation to each other around a common axis in a manner enabling said first openings being aligned and said second openings being aligned in an opening position, and enabling said first openings being un-aligned and sealed; and said second openings being un-aligned and sealed in a closing position.
 2. A lid of claim 1, wherein the circular upper portion comprises a guiding member and the circular lower portion comprises a counterpart guiding member, where said guiding members are configured to guide said circular upper and lower portions to be attached to and detach from each other in predefined position, when said guiding members are aligned with each other in same line.
 3. A lid of claim 1, wherein said circular upper or lower portions comprises tactile providing mechanics for providing tactile feedback, when said circular upper portion is turned in relation to said circular lower portion to said opening or closing positions.
 4. A lid of claim 1, wherein the circular upper portion comprises a tactile feedback member and the circular lower portion comprises a counterpart tactile feedback member, where said tactile feedback member and said counterpart tactile feedback member are configured to provide tactile feedback and guide said first openings being aligned to stop and said second openings being aligned to stop in an opening position, closed positions, when said circular upper portion is turned in relation to said circular lower portion.
 5. A lid of claim 4, wherein the tactile feedback member comprises a snap member and the counterpart tactile feedback member comprises a half-cut.
 6. A lid of claim 1, wherein the circular upper portion comprises a stop member, comprising as a protruding lip member and the circular lower portion comprises a counterpart stop member, comprising a counterpart protruding lip member, where said stop member and said counterpart stop member are configured to: guide said first openings to stop in an un-aligned and closing position and said second openings to stop in an un-aligned and closing position, guide the bayonet fastening device and the counterpart bayonet fastening device to stop in a detaching or attaching position, or preventing any additional mutual turning of said circular upper and lower portions when said circular upper portion is turned in relation to said circular lower portion, and preventing any additional mutual turning of said circular upper and lower portions.
 7. A lid of claim 2, wherein at least one of said guiding members, said tactile providing mechanics or said stop members are arranged in at least one of said bayonet fastening device.
 8. A lid of claim 1, wherein the circular upper portion is additionally provided with a sealing member, comprising a silicon sealing member or elastomer, said sealing member arranged to be positioned between said circular upper and lower portions, when said circular upper and lower portions are coupled to each other, and whereupon said sealing member is configured to seal any conduits between first openings as well as between said second openings, when said openings are un-aligned in said closing position.
 9. A lid of claim 8, wherein the sealing member is configured to be manually detachable from the circular upper portion.
 10. A lid of claim 1, wherein the circular lower portion comprises fastening thread arranged to fasten and unfasten said lid to and from said drinking container, when said circular lower portion is turned in relation to said drinking container.
 11. A lid of claim 1, wherein said lid is configured, in the lock position, to further tighten the fastening of the thread between the drinking container and the lid when applied an additional turning force.
 12. A lid of claim 1, wherein the circular lower portion is provided with a sealing member, comprising a silicon sealing member or elastomer, said sealing member arranged to be positioned between said circular lower portion and the drinking container, when said circular lower portion and the drinking container are coupled to each other and sealed.
 13. A lid of claim 1, wherein a top surface of the circular upper portion comprises an asymmetrically shaped portion or is asymmetrically shaped for better user drinking experience.
 14. A lid of claim 1, wherein a top surface of the circular upper portion comprises a matte or rough outer surface for increasing turning grip.
 15. A lid of claim 1, wherein said first and second openings of the circular upper or lower portion are provided with sealing members, wherein said sealing members are arranged to be pressed against the circular upper or lower portion in a non-opening position in a liquid-tightly sealing manner.
 16. A lid of claim 1, wherein the circular lower portion comprises two structural portions, one of which comprises hard material and one of which comprises softer portion functioning as a sealing member.
 17. A lid of claim 1, wherein said circular upper portion comprises two structural portions, one of which comprises hard material and another portion of which comprises softer portion functioning as a sealing member.
 18. A lid of claim 1, wherein said circular upper portion and said circular lower portion are configured to be coupled with each other in a releasable manner via said bayonet fastening devices.
 19. A drinking container comprising a lid wherein the lid comprises: a circular upper portion comprising a bayonet fastening device, and a circular lower portion comprising a counterpart bayonet fastening device, wherein: said circular upper portion comprises a first and second openings and said circular lower portion comprises corresponding first and second openings, wherein: said bayonet fastening device of the circular upper portion and said counterpart bayonet fastening device of the circular lower portion are configured to be coupled with each other so to guide the circular upper portion and the circular lower portion to be turned in relation to each other around a common axis in a manner enabling said first openings being aligned and said second openings being aligned in an opening position, and enabling said first openings being un-aligned and sealed; and said second openings being un-aligned and sealed in a closing position.
 20. A manufacturing method of a lid for a drinking container, wherein the lid comprises: a circular upper portion comprising a bayonet fastening device, and a circular lower portion comprising a counterpart bayonet fastening device, wherein: said circular upper portion comprises a first and second openings and said circular lower portion comprises corresponding first and second openings, wherein: said bayonet fastening device of the circular upper portion and said counterpart bayonet fastening device of the circular lower portion are configured to be coupled with each other so to guide the circular upper portion and the circular lower portion to be turned in relation to each other around a common axis in a manner enabling said first openings being aligned and said second openings being aligned in an opening position, and enabling said first openings being un-aligned and said second openings being un-aligned in a closing position. 